Uridines Modified with Sulfur or Selenium in U-G Wobble Pairs Matter for tRNA Function

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Transfer RNAs (tRNAs) are essential molecules for protein synthesis, acting as adaptors between messenger RNA (mRNA) codons and amino acids.
• Over 100 modified nucleosides exist in tRNAs, with many located at the anticodon's wobble position (position 34).
• These modifications are critical for tRNA integrity, function, and accurate translation.

Purpose of the Study:

• To review the role of sulfur- and selenium-modified uridines at the tRNA wobble position.
• To discuss their physicochemical properties and regulatory functions in gene expression.
• To examine their impact on decoding synonymous codons and base pairing.

Main Methods:

• Literature review focusing on sulfur- and selenium-modified uridines.
• Analysis of physicochemical properties and regulatory functions.
• Examination of anticodon base pairing with mRNA codons (5'-NNA-3' and 5'-NNG-3').
• Theoretical calculations on base pair stability and structural analysis in tRNA-mRNA-ribosome complexes.

Main Results:

• Sulfur- and selenium-modified uridines at the wobble position enhance decoding of specific codons.
• These modifications facilitate efficient uridine-adenosine and uridine-guanosine base pairing.
• C5 substituents on 2-thiouridines and 2-selenouridines affect tautomeric and ionization properties.
• Theoretical calculations support the importance of these modifications for translation fidelity.

Conclusions:

• Modified uridines, particularly sulfur- and selenium-containing ones, at the tRNA wobble position are vital for precise gene expression.
• These modifications optimize translation efficiency and fidelity by influencing codon recognition and base pairing.
• Understanding these modifications provides insights into the regulation of protein synthesis.